<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>order</title>
    <style>
        /*
        order: <integer>;
        order属性定义项目的排列顺序。数值越小，排列越靠前，默认为0。
        */
        .unit{
            width: 80px;
            height:50px;
            background:orange;
            margin:10px;
        }
        .box{
            display: flex;
            flex-flow:row wrap;
            border:1px solid #000;
            margin:10px;
            width: 500px;
            height:200px;
        }
    </style>
</head>
<body>
<div class="box">
    <div class="unit" style="order:1;">1</div>
    <div class="unit">2</div>
    <div class="unit">3</div>
    <div class="unit" style="order:3;">4</div>
    <div class="unit">5</div>
    <div class="unit" style="order:1;">6</div>
    <div class="unit">7</div>
    <div class="unit">8</div>
    <div class="unit">9</div>
</div>
</body>
</html>
